Management of Saltwater Intrusion in Data-scarce Coastal Aquifers: Impacts of Seasonality, Water Deficit, and Land Use

Coastal aquifers are vulnerable to saltwater intrusion (SWI) due to several drivers particularly increased water demand and groundwater overexploitation associated with population growth, reduced groundwater recharge, and lately climate change. This study examines the status of SWI in four data scarce coastal aquifers located along the Eastern Mediterranean by assessing how water cycle seasonality, water deficits, and changes in land use and land cover (LULC) have contributed to increased salinity. A framework that combines field monitoring with hydro-geochemical techniques, as well as multivariate and inferential statistical analysis was used to identify the main SWI drivers at play at each aquifer. The overall assessment showed that all four pilot areas exhibited signs of salinization with different severities. The current state of the aquifers ranged from slightly saline (TDS < 1500 ppm) to highly saline (15,000 < TDS < 31,000 ppm). While the level of the SWI was significantly correlated to the dominant land uses at each site, the extent of the water deficit played a dominant role in explaining the occurrence and intensity of observed SWI rates. The findings suggest a synergistic effect between increased water deficits and urbanization and SWI. Site specific measures are discussed for mitigating the impacts of land use, water demand and deficit towards the sustainable management of the groundwater aquifers.